Hyperbaric oxygen therapy is an established, evidence-based treatment for radiation cystitis (haemorrhagic radiation cystitis), a delayed complication of pelvic radiotherapy. It falls under "soft tissue radiation necrosis" on Health Canada's 14 recognised conditions and is publicly funded at all 11 hospital hyperbaric programmes across Canada with a physician referral. The strongest evidence comes from the RICH-ART randomised trial (Oscarsson et al, Lancet Oncology 2019; five-year follow-up published 2025).
Quick Answer
Does HBOT help radiation cystitis? Hyperbaric oxygen therapy is an established, evidence-based treatment for radiation cystitis (haemorrhagic radiation cystitis), a delayed complication of pelvic radiotherapy. It falls under "soft tissue radiation necrosis" on Health Canada's 14 recognised conditions and is publicly funded at all 11 hospital hyperbaric programmes across Canada with a physician referral. The strongest evidence comes from the RICH-ART randomised trial (Oscarsson et al, Lancet Oncology 2019; five-year follow-up published 2025).
Radiation cystitis, also called haemorrhagic radiation cystitis, is a delayed complication of pelvic radiotherapy delivered for prostate cancer (the most common single cause in Canadian practice), bladder cancer, cervical cancer, endometrial cancer, vaginal or vulvar cancer, and rectal cancer. The condition develops months to years after radiotherapy completes and presents with persistent or recurrent painless gross haematuria (often the first symptom), urinary urgency, frequency, dysuria, suprapubic pain, and reduced bladder capacity. In severe cases, ongoing bleeding can require recurrent blood transfusion, prolonged hospitalisation, urinary diversion, or even radical cystectomy.
The underlying pathology is progressive obliterative endarteritis. The small blood vessels in the irradiated bladder wall undergo radiation-induced endothelial injury that does not appear acutely but progresses over months and years after treatment. Vessel lumens narrow, sclerose, and ultimately occlude, leading to mucosal ischaemia, telangiectasia formation, ulceration, and the characteristic bleeding pattern. The bladder wall also loses elasticity and capacity through progressive submucosal fibrosis. Approximately 5 to 10 percent of patients receiving curative-intent pelvic radiation eventually develop clinically significant radiation cystitis, with prostate cancer survivors representing the largest single Canadian patient group given the volume of radiation-treated prostate cancer in this country.
Haematuria is graded clinically using the Common Terminology Criteria for Adverse Events (CTCAE) scale. Grade 1 is microscopic haematuria with no clot, no transfusion need; Grade 2 is gross haematuria with clinical follow-up but no transfusion; Grade 3 is gross haematuria requiring transfusion, IV medication, or hospitalisation; Grade 4 is life-threatening haemorrhage with major intervention indicated. HBOT response varies by grade: Grade 1-2 cystitis often responds completely or near-completely to a standard course, while severe Grade 3-4 cystitis with extensive bladder fibrosis may show only partial response and may require combined treatment with intravesical agents (formalin, alum, hyaluronic acid) or surgical intervention.
Hyperbaric oxygen therapy treats radiation cystitis through the standard mechanism for late radiation tissue injury, with specific application to the bladder wall.
The central pathological problem is urothelial hypoxia. Radiation-induced obliterative endarteritis of the small bladder vessels reduces oxygen delivery to the urothelium and submucosa, producing chronic ischaemia that drives the bleeding, telangiectasia, and fibrosis. Inside the chamber at 2.0 to 2.4 ATA on 100 percent oxygen, plasma oxygen content rises 10- to 15-fold, raising tissue pO2 in the bladder wall to several hundred mmHg during each session and bypassing the obstructed micro-vasculature. Repeated intermittent hyperoxia stimulates the release of vascular endothelial growth factor (VEGF) and other angiogenic signals, recruiting bone-marrow-derived endothelial progenitor cells to the irradiated bladder wall. Over twenty to forty sessions, capillary density at the urothelial-submucosal interface increases substantially. The new vessels persist after treatment ends, providing the durable improvement seen in long-term follow-up data including the 2025 RICH-ART five-year analysis.
In parallel, HBOT supports fibroblast activity and collagen remodelling, gradually softening the radiation-induced submucosal fibrosis and restoring some bladder elasticity. It also reduces mucosal inflammation and supports endogenous antioxidant systems in the irradiated tissue.
The biological response builds gradually rather than immediately, which is why the recommended treatment course is 30 to 60 sessions, substantially longer than for acute indications. Most responders begin to notice reduced bleeding episodes by sessions 15 to 20, with continued improvement through the rest of the course and consolidation in the months after treatment ends.
Typical Treatment Protocol
Standard course is 2.0 to 2.4 ATA on 100 percent oxygen for 60 to 120 minutes per session (most Canadian programmes use 90 minutes), delivered five days per week for 30 to 60 total sessions over six to twelve weeks. Many patients with Grade 1-2 cystitis begin to notice reduced haematuria episodes after 15 to 20 sessions; Grade 3-4 cystitis often requires the longer end of the range (50 to 60 sessions) to achieve full response. Some Canadian programmes deliver an initial 40-session block, reassess by symptom diary and (where appropriate) cystoscopy, then extend by 10 to 20 sessions if the patient is continuing to improve but has not yet reached the response plateau. Treatment is delivered as an outpatient. HBOT is typically combined with standard radiation-cystitis management as appropriate: hydration, treatment of urinary tract infection, intravesical agents (formalin, alum, hyaluronic acid) for severe ongoing bleeding, anticholinergic or beta-3 agonist medication for urgency and frequency, and (rarely) urinary diversion or cystectomy as a last resort.
Level A - Strong Evidence
Supported by high-quality RCTs and systematic reviews
The RICH-ART trial (Oscarsson et al, Lancet Oncology 2019, PMID 31537473), a multi-centre Nordic randomised controlled trial of 79 ITT patients with late radiation cystitis, showed a statistically significant 10.1-point absolute improvement in EPIC urinary total score at six-to-eight months in the HBOT group compared to standard care (95% CI 2.2 to 18.1; p=0.013). HBOT was delivered at 240 to 250 kPa (~2.4 to 2.5 ATA) for 80 to 90 minutes per session for 30 to 40 sessions.
A 2025 five-year follow-up of the RICH-ART cohort (EClinicalMedicine 2025) confirmed the durability of benefit, with sustained EPIC urinary score improvements at the long-term assessment.
The Bennett et al. Cochrane Review of HBOT for late radiation tissue injury (2016, updated 2020, 14 trials, 753 participants) found HBOT may result in complete resolution or significant improvement of bladder and rectal radiation injury.
Standard treatment course is 30 to 60 daily sessions at 2.0 to 2.4 ATA on 100 percent oxygen for 90 minutes per session. Most responders begin to notice reduced haematuria episodes after 15 to 20 sessions.
Publicly funded as a Health Canada-recognised indication at all 11 hospital hyperbaric programmes under OHIP, MSP, AHCIP, RAMQ, MSI, MCP, and Saskatchewan Health.
Earlier referral after symptom onset is associated with better outcomes; advanced submucosal fibrosis is harder to reverse than acute haemorrhagic-phase disease.
Response varies by haematuria grade: Grade 1-2 cystitis often responds completely or near-completely to a standard course; Grade 3-4 cystitis with extensive bladder fibrosis may show only partial response and may require combined treatment with intravesical agents (formalin, alum, hyaluronic acid).
Highest-evidence-tier studies tagged to this condition in the Canada Hyperbarics research database, ranked by evidence tier (1 = meta-analysis or RCT, 2 = cohort, 3 = case series), most recent first.
Int J Urol · 2020 · Systematic Review
Int J Radiat Oncol Biol Phys · 2013 · Prospective Study
Neurourol Urodyn · 2026 · Study
Cureus · 2025 · Retrospective Study
Studies in our database that include a ClinicalTrials.gov registration. Trial registration is a marker of methodological rigour because the protocol, primary outcome, and analysis plan are deposited before enrolment begins.
EClinicalMedicine · 2025 · RCT · PMID 40291346
Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2022 · Clinical Study · PMID 35320424
Lancet Oncol · 2019 · RCT · PMID 31537473
Most patients are referred to a hospital hyperbaric programme by their urologist, radiation oncologist, or the original cancer-care team after the radiation cystitis diagnosis is confirmed (typically on cystoscopy with biopsy where appropriate to exclude bladder cancer recurrence). The hyperbaric medicine team confirms eligibility, reviews imaging and cystoscopy findings, and books the treatment course. Pre-treatment work-up includes a baseline cystoscopy report, current haematuria grade, and a discussion of any other ongoing radiation-related complications.
Daily sessions begin within two to six weeks of consultation, depending on programme wait times. You change into cotton scrubs (no synthetic fabrics, no skin lotions, no jewellery), enter the chamber, and lie down (in a monoplace) or sit in a recliner (in a multiplace with multiple patients). Pressurisation takes five to ten minutes and feels like the descent in an aircraft. The 90-minute treatment phase is on 100 percent oxygen at 2.0 to 2.4 ATA. Decompression takes another five to ten minutes. Total time on-site is typically two to three hours per visit.
Response is tracked by symptom diary (haematuria episodes, transfusion requirements, urgency-frequency-pain symptoms) at each visit and by serial cystoscopy where indicated. The hyperbaric medicine team coordinates closely with urology throughout the course. Most patients tolerate the full course well; common side effects are temporary near-sightedness during treatment (usually resolves within a few weeks of stopping), ear barotrauma (managed with pressure-equalisation techniques), and mild fatigue.
Radiation cystitis is publicly funded as a Health Canada-recognised indication (categorised under soft tissue radiation necrosis on the UHMS list under recognised condition #11, Delayed Radiation Injury) at all 11 hospital hyperbaric programmes in Canada. Coverage applies under OHIP, MSP, AHCIP, RAMQ, MSI, MCP, and Saskatchewan Health.
The Canadian patient population is large and growing. Prostate cancer is the most commonly diagnosed cancer in Canadian men, with an estimated 29,300 new cases in 2026 according to the Canadian Cancer Society. Radiotherapy (external-beam, brachytherapy, or both) is delivered in a substantial proportion of these cases, and 5 to 10 percent of treated patients develop clinically significant radiation cystitis over the years following treatment. Cervical cancer (an estimated 1,650 new cases in 2025, with most patients receiving pelvic radiation) and bladder cancer (an estimated 12,600 new cases in 2025, some receiving definitive or post-cystectomy radiation) add to the population at risk.
Referral pathway is urology, radiation oncology, or the treating cancer-care team referring to the nearest hospital hyperbaric programme. Wait times vary substantially by province. In Nova Scotia, chronic and elective radiation-cystitis cases at the QEII commonly wait 12 to 18 months. In Ontario, Quebec, BC, Alberta, and Newfoundland, scheduling depends on the specific programme's capacity and current case load. Patients in provinces without a hospital chamber (PEI, Manitoba, New Brunswick, Yukon, Northwest Territories, Nunavut) are referred interprovincially through their physician, with most cases routing to Misericordia Edmonton (for prairie and territorial patients) or the Ontario hospital programmes.
Hyperbaric oxygen therapy for the 14 Health Canada-recognised conditions, including Radiation Cystitis, is delivered at the 11 hospital hyperbaric programmes located in seven provinces (Ontario, Quebec, British Columbia, Alberta, Nova Scotia, Newfoundland and Labrador, and Saskatchewan). The six provinces and territories without an in-province hospital programme (Manitoba, New Brunswick, Prince Edward Island, Yukon, Northwest Territories, and Nunavut) route patients to the nearest receiving hospital programme. Use the links below for province-specific coverage, referral pathway, and emergency routing details.
Hospital + Private
OHIP (Ontario Health Insurance Plan)
Hospital Only
MSP (Medical Services Plan)
Hospital + Private
Alberta Health / AHCIP
Hospital Only
RAMQ
Disrupted
Saskatchewan Health Authority
No Hospital Chamber
Manitoba Health
Hospital Only
MSI (Medical Services Insurance)
No Hospital Chamber
Medicare NB
Hospital Only
MCP (Medical Care Plan)
Out-of-Province Referral
Health PEI
Out-of-Province Referral
Yukon Health and Social Services
Out-of-Province Referral
NWT Health and Social Services
Out-of-Province Referral
Nunavut Department of Health
For acute or emergency presentations of Radiation Cystitis, call 911 first. The receiving emergency department coordinates urgent transfer to the nearest hospital hyperbaric programme through the relevant provincial transfer network (CritiCall Ontario at 1-800-668-4357, BC Patient Transfer Network, EHS Nova Scotia, or equivalent). For diving-related emergencies, the Divers Alert Network (DAN) emergency hotline is 1-919-684-9111.
Untreated pneumothorax is the only absolute contraindication. Concurrent treatment with bleomycin or disulfiram are formally contraindicated. Relative contraindications include severe chronic obstructive pulmonary disease with bullous lung disease, uncontrolled seizure disorder, claustrophobia (manageable in monoplace chambers), recent middle-ear or sinus surgery, and uncontrolled hypertension. Active bladder cancer (as opposed to post-treatment late effects) is typically not a contraindication for radiation cystitis HBOT, but the treating cancer-care team makes the final decision; cystoscopy with biopsy to confirm no recurrence is standard pre-treatment work-up. Ongoing severe haematuria requiring active transfusion may need stabilisation through intravesical agents before HBOT can be safely delivered as an outpatient.
Yes. Radiation cystitis is publicly funded as part of "soft tissue radiation necrosis" under Health Canada's 14 recognised hyperbaric indications. Treatment at all 11 hospital hyperbaric programmes is covered by OHIP, MSP, AHCIP, RAMQ, MSI, MCP, and Saskatchewan Health with a physician referral. Patients in provinces without a hospital chamber are referred interprovincially.
The RICH-ART RCT (Oscarsson et al, Lancet Oncology 2019) showed clinically meaningful and statistically significant improvement in patient-reported urinary symptoms (10.1-point absolute improvement in EPIC urinary score, p=0.013). The 2025 five-year follow-up published in EClinicalMedicine confirmed sustained benefit. The 2016 Bennett Cochrane Review of late radiation tissue injury (14 trials, 753 participants) supports HBOT for bladder and rectal radiation injury. Many patients experience complete resolution or significant symptom improvement, especially when treated earlier in the disease course.
A typical course is 30 to 60 daily sessions at 2.0 to 2.4 ATA on 100 percent oxygen for 90 minutes per session, delivered five days per week over six to twelve weeks. Grade 1-2 cystitis often responds within 30 to 40 sessions; Grade 3-4 cystitis with extensive bladder fibrosis often requires the longer end of the range. Most responders begin to notice reduced haematuria episodes after 15 to 20 sessions.
Yes. Grade 1-2 cystitis (microscopic haematuria or gross haematuria not requiring transfusion) often responds completely or near-completely to a standard course. Grade 3-4 cystitis (transfusion-requiring or life-threatening haemorrhage) with extensive submucosal fibrosis may show only partial response and may require combined treatment with intravesical agents (formalin, alum, hyaluronic acid). Earlier referral after symptom onset, before extensive fibrosis develops, is associated with better outcomes.
Speak with your urology team, radiation oncology team, or the cancer-care provider who treated your original cancer. They can send a referral to the nearest hospital hyperbaric programme. Pre-treatment work-up typically includes a baseline cystoscopy with biopsy to exclude bladder cancer recurrence, current haematuria grade documentation, and a discussion of any other ongoing radiation-related complications.
For many patients HBOT achieves substantial and durable improvement, including in some cases complete resolution of bleeding and symptoms. The likelihood of complete resolution depends on severity (haematuria grade), time since onset, extent of submucosal fibrosis, and individual patient factors. The 2025 five-year RICH-ART follow-up data support sustained benefit beyond the immediate treatment course, with most responders maintaining their gains.
Yes, this is a recognised late effect of pelvic radiotherapy and a common reason for HBOT referral in Canada. Radiation cystitis develops months to years after radiotherapy completes; some patients first present a decade or more after their original treatment. Speak with your family physician or urologist promptly. They will arrange cystoscopy with biopsy to confirm the diagnosis and exclude bladder cancer recurrence, then refer you to the nearest hospital hyperbaric programme. Earlier referral, before extensive fibrosis develops, is associated with better outcomes.
All 11 Canadian hospital hyperbaric programmes accept radiation-cystitis referrals. The Canada Hyperbarics verified directory at canadahyperbarics.ca/facilities/ lists all programmes with phone numbers, addresses, and current operational status. Coverage details for every province are at canadahyperbarics.ca/hbot-coverage-canada/.